My Fridge was turned off

Question

My Fridge was turned off for the winter while I was away. Unfortunately my plumber left filled ice cube trays in the freezer and shut the door. Water was also left in the fridge. When I returned this year there was some black mold in the fridge and freezer. My question is whether the mold could also be in the insulation parts of the fridge that I cannot reach. And if by ridding the available interior of the unit of this mold, the fridge is safe to use?